Cement Energy and Environment

of a suitable size in the second unit. Table 2 Accordingly three butterfly Pressure drop across butterfly dampers dampers were replaced with three vane dampers and a detai led study was carried out to assess the Fan No. RPM Flow, m 3 /min Difference 100% Operating m 3 /min KIO 2310 520 300 220 Kll 1800 800 510 290 K12 1725 830 540 290 Kl3 1660 780 592 188 Kl4 1660 780 520 260 Kl6 1225 1180 860 320 Average spectfic pressure drop across butteifly damper From these two experiments it became apparent that pressure drop across butterfly dampers is very high compared to that across vane dampers. The total volume flow in the second unit cooler fan was . regulated from 6940 m 3 /min to 4837 m 3 /mi n at normal operating conditi ons. Table 3 shows the comparative pressure drop for buuerll y and vane damper to regulate the above said fl ow. Table 3 Pressure Specific drop mmWG 190 180 145 139 160 105 Pressure drop mmWG/ m 3 /min 0.864 0.621 0.500 0.739 0.615 0.328 0.616 pressure drop across the vane dampers and the corresponding power consumption of the fan s at di ITercnt llow conditions. The variation in power consumption of the fans at ditlerent operating flow va lues, while using buttertly and vane dampers, is represented by curves Rl and R2 respectively in Figure 2. 200· ~-------------·- -··---- 141 130 · ·' ... · .. s.~.V.·~~ .. ~~ .. P.~:".~r. ......... ........... ... . Fo: ane dampP.rs Operattng I00 100 300 400 500 600 700 800 f;gure 2 Power and volume cun•e of K-13 cooler fan with butterfly and vane dampers Comparative Pressure Drop for Butterfly and V.m,· D:uuprr:c; Damper Flow rate m~/min Specific Total type 100% Operating Pressure Pressure Drop Drop mmWG/ mmWG m 3 /min Buttertly 6940 4837 0.616 1295 Vane 6940 4837 0.321 675 It is clear from Table 3 that if buttcrny dampers in all cooler fans arc replaced with vane dampers, a saving of 70kW can be achieved. It was decided to check the extent of power saving by actuall y replacing butterlly dampers with vane dampers [t is dear from Figure 2 that at an Average Power los. Pressure due to operating value of 520m 3 /min Drop Pressure mmWG drop kW there will be a power saving of up 185 146 to 12 amps ( 142- 130) when 96 76 butterfly dampers arc replaced with vane dampers. For this purpose, four vane dampers have been fabricated in the site workshop and fi xed in place of the butterlly damper actuators. The performance of the cooler fans with butterlly and vane dampers is compared in Table 4. 5